Choke coil



Aug; 11, 1931. ZUHLKE 1,818,186

CHOKE COIL Filed Sept. 4. 1950 INVENTOR. /%1tr/Z0"/?/ke.

ATTORNEY,

Patented Aug. 11, 1931 I UNITED STATES PATENT OFFICE nncEL'zflnLxn, ornnnnm-wmssnnsnn, GERMANY, assronon TO wnsrmonousn nnnc'rnrc axannraoronmo comramr, A conromrron or PENNSYLVANIA Application maSeptember 4,1930, Serial lid-179,614, a... in Germany September 4, 1929.

My invention relates to improvements in choke coils and moreparticularly to choke coils constructed of flat sectional coils.

, "When a choke coil consistin 'offlat sec- 3 tional coils of theconstruction hitherto known in the art, becomes hot in service, theheated air in the neighborhood of the coil system ascends. The coolingeffect roduced I on the system by the rising air is, wever,

comparatively poor; the reason for this being, onthe one hand,'that agreat part ofthe air put into motion by the heat does not come intocontact at all with any of the heat emitsurfaces of the coilsystem and,on the It? other'hand, that the rising air, so far as it does come intoimmediate contact with the coil system, only does so essentially on theouter and inner edges of the sectional coils but not on the surfaces ofthe fiat coils where air they face one another. For this reason and alsobecause only a com aratively small part of the whole surface the coilsystem can radiate heat outwardly, a considerable ac- I cumulation ofheat takes place between the '26 sectional coils. I

According to the present invention, the above disadvanta e which causesa comparatively very considerable reduction in theca- A V pacity of thechoke coil, is eliminated by conmr ducting the cooling air currentthrough the apparatus in a special manner. A cooling air draft which canbe advantageously produced by creating a chimney efiect, and may also beincreased by the employment of a fan, is made to pass through the chokecoil partly in radial and partly in axial direction, so that the coolingair comes into contact with all the heat-emitting surfaces, andparticularly with the parallel faces of the coils. Besides, the bestpossible relation is obtained between the volume of cooling air passingthrough the apparatus and the size of the surfaces to be cooled. g

In Figs. 1, 2 and 3 of the accom n ing drawings, various constructions oc oke coils of the above described kind are shown" by way of example.

' Fig. 1 shows a cross section of a singlehase choke coil constructedaccordi to the 5 of insulatin material. The opening n, of

the bottom coi s, is closed by a closing piece u.

On the top flat coil, is arranged a chimneylike extension 0. Both theclosing piece u and the chimneydike extension amay be made completely ofa suitable insulating material, but it is mostly more practical to makethe extension (1 of a non-ma netic metal coated with aninsulatingmaterial. A choke coil of that kind re resents altogether a kind ofchimney, in whidli cooling air is constantly pressed through theinterspaces between the sectional coils s s s a, into the middle ofthe'coil system, from where it flows off as warm air through theextension (1 into the open. In this manner, all the cooling current 0air flowing through the system of coils is obligedto absorb heatproduced in the winding's, and at the same time all the surfacesemitting heat are exposed to a continual and uniform current of freshair. The desired intensive cooling of the coil is thereby obtained.

In Fig. 8, a three-phase choke coil is illustrated, consisting of threegroups g g g, of

sectional coils. Between the individual groups, are arrangedintermediate chimneyllke parts a, and s made of insulating material, or,if more advantageous for the particular case, of non-magnetic metal,coated with insulating material. The effect is in principle the same aswith the aforedescribed single- Ehasechoke coil. The intermediatechimney- 'ke pieces z and 2 may bemade sufliciently strong to withstandthe forces caused by ,shortcircuits occurring in service.

In order to obtain a particularly intensive cooling effect with chokecoils of this. kind,

the chimney-like extension may be made much longer than shown in'theexamples given in the drawings; it may also, for instance, be connectedonto aflue. 7

If the existing conditions are particularly unfavorable, thechimney-effect can be partly substituted by a fan built for example intothe top extension a as shown in Fig. 8 for the three-phase choke coil.

The decisive advantage of choke coils con structed according to myinvention consists in that they are in the simplest manner inade capableof carry ng a considerably greater load.

I claim as my invention:

1. A choke coil, consisting of several fiat sectional coils with anopening in the middle and arranged the one above the other at t certaindistance from one another, means for npperting said sectional coilsleaving room between these coil for a cooling medium to pass. and a clcpiece, preferaoly o insulatimmaterial. faened to the bottom sectionalcoil and closing the opening of this 2. A choke coil. Consisting ofseveral tat sectional coils with an op *nrng 1n the nndcle and arrangedon: above e otl'ier 2b 2 tae ii certain distance from one anot ier,means for inpporting saic sectional coils lein'in; room between thesecoils for a cool'ag medium to pass. :1 c )sing piece, preferably of:nlatinn material, fastened to the bottom of scctiona coil and closingthe opening of this coil. and a chimney-like extension on the topsectional coil. paid chimney-like extension consisting preferably ofmetal covered with insulating material.

3. A choke coil, consisting of sever 1: -etlioaal coils with an openingin the 1 iidd and arranged the one above the other at a certain distancefrom one another, n'ieais for supporting said sectional coils leavingroom between the coils for a c oling medium to pass. closing piecepreferably of insulating material fastened to the bottom sectional coiland clos' the opening of this coil, a chimney-like extension on the topseetioi coil, said chimney-like extension consistii erably of metalcovered with insnlat tcrial, and a ventilator in said chini re listextension suitable for 11li1l(ia cooling niedinm pass between the ind*idnal flat coils and through the opening of these coils.

l. A choke coil cons: v of several groups of tlat sectional coils. dgrin. being arrai god above one anoth r. salt flat sectional co; of eachmiddle and up havi i opening in the ed t e one above th me another.means leavers;

for snppo room he w to giin mater" id c nedinin e coi s for a C055 neceprcterab ning this coil, be-

coils chi nine};-

i. A ictic a min iasaiatina ina 4 l1.

o. A choke coil consisting of several groups of flat sectional coils,said groups being arranged above one another, said flat sectional coilsof each group having an opening in the middle and being arranged the oneabove the other at a distance from one another, means for supporting theindividual coils, leaving room between the coils for a cooling medium topass. a closing piece, preferably of insulating material, fastened tothe bottom sectional coil and closing the opening of this coil, betweenthe groups of ional coils chimneylilre intermediate pieces. preferablyof nonmagnetic metal, coated with insulating material. and on the topsectional coil :1 chimney-like extension preferably of metal covd withinsulating? aterial.

.f1\ ch' coil in f several groups f ats-" .ton. i. said gronrs being ar-1., alzove oneanother. said flat sectional f each group having anopening in the el the one above the 21 cc fr-rnn one another, means theindividual coils. leaving 11 coils for a cooling mepiece preferably ofin a l '-l1l(e (.Ii'QDSiOZE, preferably of metal cove op sectional coil2 chimmaterial.

cred with insnlat and in said chinn'iev-lilie extension a tan suitablefor malt a cooling niednnn pass between the and through the openings J.1.4 .Lll V1231,

have herenntt subthis )l'h day' of Angost,

Mancini zt i niitn.

inony \vhereo scribed my name 1930.

